• Korean Journal of Agricultural and Forest Meteorology
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• v.13 no.3
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• pp.140-147
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• 2011

We studied the influence of livestock waste leachate on oxidative damage and antioxidative responses in poplar clones in August which increase the demand of antioxidants because of high temperature and high light during this period. We measured ion leakage, antioxidant enzyme activities (APX, GR), and carotenoid contents. Oxidative damage and antioxidative responses by treated livestock waste leachate in poplar clones showed various results. We divided poplar clones into three groups using the criteria based on ion leakage which represent cell damage induced oxidative stress. Eco 28, 62-10, Bonghwa1 and Dorskamp belonged to the first group in which the cell damaged level was lower than that of the control. The results suggest that this group augmented for demand of antioxidative in summer because high concentration of nitrogen induced by treatment of live stock wastes acted as environmental stress. Consequently, they failed to keep up the homeostasis of reactive oxygen species. The second group in which the cell damaged level was similar to that of the control was Suwon, 72-30 and 72-31 clones. Finally, 97-18 clone belonged to the third group in which the cell damaged level was lower than that of the control group. In this case, nitrogen treated by livestock waste leakage decreased oxidative stress. 97-18 clone was the clones with the least damage in summer oxidative stresses treated by livestock waste leakage. These results suggest that the high concentration nitrogen due to the livestock waste leakage can act differently upon the clones. We speculate that the added oxidation damage in the summer (growing season) may have an effect on the total fresh weight and also influence the purification ability for livestock waste leakage. However, further studies are needed for the confirmation.

• Journal of Wetlands Research
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• v.23 no.1
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• pp.60-66
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• 2021

As the concentration of nitrogen in the sewage flowing into the sewage treatment plant increases due to urbanization and industrialization, the degree of adverse effects such as eutrophication and toxicity to the aquatic ecosystem is also increasing. In order to treat sewage containing high concentration of nitrogen, various studies on the biological nitrogen removal process are being conducted. Existing biological nitrogen removal processes require significant costs for supplying oxygen and supplementing external carbon sources. In this respect, as a high-level nitrogen removal process with economic improvement is required, an anaerobic ammonium oxidation process (ANAMMOX), which is more efficient and economical than the existing nitrification and denitrification processes, has been proposed. The purpose of this study is to confirm the stability of the ANAMMOX process in the water treatment process and to derive the ratio of ammonia nitrogen (NH4+) to nitrite nitrogen (NO2-) for the implementation of the mainstream ANAMMOX process. A laboratory-scale Mainstream ANAMMOX reactor was operated by applying the ratio calculated based on the substrate ratio suggested in the previous study. In the initial range, the removal efficiency of NH4+ was 58~86%, and the average removal efficiency was 70%. In the advanced range, the removal efficiency of NH4+ was 94~99%, and the average removal efficiency was 95%. As a result of the study, as the NH4+/NO2- ratio increased, the stability of the mainstream ANAMMOX process was secured, and it was confirmed that the NH4+ removal efficiency and the total nitrogen (TN) removal efficiency increased. As a result, the results of this study are expected to be used as basic data in the application of the ANAMMOX process in the mainstream.

• Korean Journal of Environment and Ecology
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• v.26 no.5
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• pp.694-706
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• 2012

The purpose of this study was to offer the raw data for conservation and restoration of aquatic ecosystem by surveying and analysing a water quality, sediment, benthic macroinvertebrate, fish and hydrophyte in Junam reservoir. In the result of analysing the water quality, pH was 8.2~8.4, 6.0~7.5mg/${\ell}$ in COD, 10.0~10.3mg/${\ell}$ in SS, 8.3~11.5mg/${\ell}$ in DO, 0.1mg/${\ell}$ in T-P and 1.2~1.3mg/${\ell}$ in T-N. In case of the sediments, Cd was 0.47~0.52mg/kg, 7.08~7.43mg/kg in Cu, 0.22~0.32mg/kg in As, 0.02~0.03mg/kg in Hg, 6.20~7.45mg/kg in Pb, 32.80~39.70mg/kg in Ni, 513.0~543.0mg/kg in F and 137.0~140.0mg/kg in Zn. $Cr^{6+}$ was not detected. The benthic macroinvertebrates were 432 individuals including 3 phyla, 5 classes, 9 orders, 26 families, 33 genera and 39 species, and the ecological score of benthic macroinvertebrate community(ESB) was 25. The fishes were 8 families and 14 species, and the invasive alien species were 2 taxa including Micropterus salmoids and Lepomis macrochirus. The hydrophytes were 63 taxa including 28 families, 42 genera, 56 species, 1 subspecies and 6 varieties. The emergent plants were 38 taxa(60.3%), 5 taxa(7.9%) in floating-leaved plants and each 10 taxa(15.9%) in free-floating plants and submerged plants.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.1
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• pp.1-10
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• 2005

The purpose of this study was to evaluate the potential of a gamma irradiation to decompose 2,4,6-trinitrotoluene(TNT) in an aqueous solution. The decomposition reaction of TNT by gamma irradiation was a pseudo first-order kinetic over the applied initial concentrations($25{\sim}100mg/L$). The dose constant was strongly dependent on the initial TNT concentration. The removal of TNT was more efficient at pH below 3 and at pH above 11 than at neutral pH(pH 5-9). The required irradiation dose to remove over 99% of TNT was 40, 80 and 10 kGy, individually at pH 2, 7 and 13. The dose constant was increased by 1.6 fold and over 15.6 fold at pH 2 and 13, respectively, when compared with that at pH 7 When irradiation dose of 200 kGy was applied, the removal efficiencies of TOC were 91, 46 and 53% at pH 2, 7 and 13, respectively. Ammonia and nitrate were detected as the main nitrogen byproducts of TNT and glyoxalic acid and oxalic acid were detected as organic byproducts. The results showed that a gamma irradiation was an attractive method for the decomposition of TNT in an aqueous solution. However, regarding the application of high energy radiation for the TNT decomposition and mineralization, an application of an acidic pH below 3 to the solution before irradiation should be considered.

• Korean Journal of Environmental Agriculture
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• v.20 no.4
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• pp.252-257
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• 2001

To get the basic information for the water quality improvement and control of water resource at Mankyeong river stream, the water quality in four site of main stream and three site of branch stream at the upper stream were investigated mainly from February to August in 2000. The water temperature was affected by depth, flow rate of the water, and air temperature, and ranged 6.4 to $30.8^{\circ}C$. The pH, DO and BOD values of the water was $5.9{\sim}9.7$, $4.6{\sim}14.50\;mg/L$, and $0.1{\sim}11.8\;mg/L$ range, respectively. The content of total nitrogen, $NO_3-N$ and $NH_4-N$ was $1.19{\sim}10.61\;mg/L$, $1.00{\sim}5.93\;mg/L$, and ND $(non\;detected){\sim}2.79$ mg/L, respectively. The concentration of total phosphorus was ND to 1.14 mg/L. The concentration of Cl ion was $3.5{\sim}196.4\;mg/L$. The content of Fe and Mn was $0.002{\sim}0.100\;mg/L$ and $ND{\sim}0.04\;mg/L$, respectively. The contents of heavy metal Cd, Cu, and Zn were $ND{\sim}0.03\;mg/L$, $ND{\sim}0.05\;mg/L$, and $0.001{\sim}0.17\;mg/L$, respectively. Pb was not detected in all the samples. The pH, total nitrogen contents, and total phosphorus content were frequently exceeded the water quality standard for agriculture. The degree of water pollution was very varied by the sampling place. The water quality was generally polluted in the dry season more than in rainy season. The highest level of water pollution observed in the area of Samyea Bridge among the 7 sites.

• Korean Journal of Microbiology
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• v.39 no.2
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• pp.95-101
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• 2003

The total bacterial numbers, Eubacterial community structures and environmental factors which affect bacterial community were estimated monthly using DAPI and fluorescent in situ hybridization monthly, from June to November 2000 to evaluate the correlation between the bacterial community and environmental factors in eutrophic agricultural Masan reservoir in Asan. Average water temperatures varied from 12.3 to $27.5^{\circ}C$, pH 7.5 to 9.0, DO 7. I~12.8 mg/L, COD 6.4~13.0 mg/L, chlorophyll a 30.5~99.0 mg/㎥, SS 7.S~25.7 mg/L, TN 1.748~3.543 mg/L., and TP 0.104~0.581 mg/L, respectively. Total bacterial numbers showed high ranges from 0.4 to 9.6$\times$ $10^{6}$ cells/ml, and these indicated the mesotrophic or eutrophic state. The ratio of Eubacteria to total bacteria was 67.6-88.0%, which was higher than that in other reservoir. The relationships of total bacteria and Eubacteria community were more significant with organic nitrogen (Org-N), and organic phosphorus (Org-P) than with water temperature. Proteobacteria groups showed strongly significant relationships with Org-P and Org-N and significant relationships with water temperature, conductivity, COD, and inorganic nitrogen. C-F group was the most significant with Org-N, and HGC group with water temperature. However, relationships of Chl-a, pH, DO and SS showed no significance with any bacterial community. These results were different from other studies, because of the specific characteristics of Masan reservoir such as old, shallow and eutrophic states. The seasonal variation of bacterial community in Masan reservoir does not seem to depend on phytoplankton dynamics but on storm event and organic materials from watershed and the sediment of reservoir.

• Journal of Aquaculture
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• v.11 no.3
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• pp.391-400
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• 1998

This study was performed to investigate the effects of environmental parameters on the growth of Pacific oyster, Crassostrea gigas at old suspended culturing grounds of Korsung Bay and newly deveoped bottom, culturing grounds of Haenam region located in southern coast of Korea. The Kosung Bay was semiclosed and water exchange occurred through the small mouth and the current speed was very slow as the value of below 0.5kn. Haenam was opened and littoral zone. Current speed of the surroundings of this Bay about to 5.0knand transparency was low with the mean depth of 1.2m by the resuspension of the sediments. Water temperature and salinity regimes were suitable for oysters at those sites, however the mean value of those parameters and seasonal fluctuations was high at Kosung. The mean concentration of dissolved oxygen in survey area was above $5.0mg/\ell$. In Kosung, however, it was decreasing in June and showed the minimum with the concentration of $4.0mg/\ell$ in August at the bottom layer and recovered in September. Eutrophication parameters such as COD were 1.44 mg/l at this location. This mean value was higher than that of the Haenam Bay's $0.96mg/\ell$. The men value of chlorophyll-$\alpha$ at Haenam was two times higher than the other sites. Growth of shell height and meat weight of oysters at Kosung Bay were higher and the fatness was lower compared to thost of Haenam. As a result, absolute growth of oysters was high at Kosung and allometric growth, such as fatness, was good at Haenam. Low water temperature and frequent exposure of oysters to the air during ebb tide may retard the shell growth. On the other hand, relatively high food availability was profitable for the fatness at haenam site.

• Korean Journal of Food Science and Technology
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• v.38 no.3
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• pp.452-455
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• 2006

The in vitro cytoprotective and anti-oxidative effects of ursodeoxycholic acid, a major active compound from bear's gall were investigated in mouse brain microglia. In the present study, we wished to scrutinize the potential role of UDCA as an anti-neurodegenerative agent in neurodegenerative disease such as Alzheimer's disease. This concept was supported by the multiple preliminary studies in which UDCA has an anti-inflammatory effect in microglial cells. In the study, we found that $7.5\;{\mu}g/mL$ UDCA was effective in the protection of cells from $H_2O_2$ damage, a reactive oxygen, and the resuIt was coincided with the anti-apoptotic effect in DAPI staining. Moreover, the metal-catalyzed oxidation study showed that UDCA has antioxidant effect as much as ascorbic acid at $50{\sim}100\;{\mu}g/mL$. In conclusion, these study results suggested that neuro-degenerative diseases such as Alzheimer's disease probably caused by over-expressed beta amyloid peptide in elderly people can be controled by UDCA through an anti-inflammatory, anti-oxidative and anti-apoptotic effect. The evidences showed in the study may be references for more in-depth in vivo and clinical studies for a candidate of anti-neurodegenerative therapy in the near future.

• Clinical and Experimental Pediatrics
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• v.48 no.12
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• pp.1330-1336
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• 2005

Purpose : It has been suggested that changes in cerebral blood flow by ventilator care could be a risk factor in periventricular leukomalacia(PVL) and severe periventricular-intraventricular hemorrhage(PV-IVH). The study aims to assess the relationship between perinatal clinical events, including ventilator care, and the development of PVL and severe PV-IVH; especially, whether ventilator care could be causers of PVL and severe PV-IVH as an individual risk factor. Methods : Among 255 very low birth weight infants who survived in the Fatima neonatal intensive care unit from January 1999 to December 2003, 15 infants with PVL and eight infants with severe PV-IVH were classified as a study group, while 231 infants were enrolled as a control group. The analysis was performed retrospectively with medical records. Results : Twenty four infants were diagnosed with PVL or severe PV-IVH. Asphyxia, recurrent apnea, sepsis, acidosis and ventilator care were significantly increased in the PVL goup. Asphyxia, recurrent apnea, RDS, acidosis and ventilator care were significantly increased in the severe PV-IVH group. Conclusion : Infants with PVL or severe PV-IVH may have multiple perinatal risk factors including asphyxia, recurrent apnea, sepsis, acidosis, RDS and ventilator care. Because most patients with ventilator care have multiple perinatal risk factors, ventilator care does not cause PVL and severe PV-IVH independently. Therefore, incidences of PVL and severe PV-IVH can be decreased by not only gentle ventilation, but also more professional antenatal care.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.6008-6014
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• 2013

This study aimed to understand seasonal variation of physico-chemical factors and biomass of size-fractionated phytoplankton at Ulsan seaport during the period from February 2007 to November 2009. Water temperature, salinity, dissolved oxygen (DO), pH, chemical oxygen demand (COD) and total suspended solid (TSS) varied in the range of 8.94-$24.26^{\circ}C$, 25.06-34.54 psu, 4.30-10.73 mg/L, 7.97-8.53, 0.66-40.70 mg/L and 57.4-103.3 mg/L, respectively. These factors showed no clear spatial variation unlike spatial pattern of inorganic nutrients and total chlorophyll-a (chl-a) concentration as biomass. Concentration of phosphate, nitrate and silicate ranged from 0.01 to 3.03 ${\mu}M$, 0.05 to 21.62 ${\mu}M$, and 0.01 to 27.82 ${\mu}M$, respectively, with 2 times higher concentration at inner stations than that at outer stations during the study period. Within the range of total chl-a concentration (0.36-7.11 ${\mu}gL^{-1}$), higher concentration (avg. 1.88 ${\mu}gL^{-1}$) of total chl-a were observed at inner stations compared to that (avg. 0.90 ${\mu}gL^{-1}$) at outer stations. Micro-sized phytoplankton dominated total biomass of phytoplankton in spring (34.0-81.2%), summer (35.1-65.6%) and winter (3.9-62.0%). Nano- and pico-sized phytoplankton contributed 58.2-74.5% and 22.4-38.2% to total biomass of phytoplankton in autumn, respectively. However, contribution in biomass of size-fractionated phytoplankton to total phytoplankton biomass showed no clear difference between inner and outer stations. Consequently, these results indicated that spatio-temporal distribution of phytoplankton biomass at Ulsan seaport was dominated by micro-phytoplankton (avg. 52.3%) during the study period except autumn, which was closely dependent on the concentration of inorganic nutrients (p<0.05).